Efficient muco-ciliary clearance is maintained by a multi-regulatory system complex. The prime objective of the proposed work is to elucidate the fundamental organization and behaviour characteristics of the regulatory system complex by a comprehensive approach. Further refinement of the model of muco-ciliary clearance and development of the basis for a rational approach to prevention and treatment of chronic lung diseases related to environmental noxious agents is our ultimate goal. Relying on a chemical and rheological joint approach, studies will be carried out to fully explore the molecular structure of respiratory mucus glycoproteins with a special focus on the nature of intermolecular crosslinks, and to elucidate the rheological and structural relationship. Based on the structural information, efficient and meaningful micromethods for chemical profile characterizations of major components of mucus secretions will then be developed. As such methods become available, the study will further be extended to elucidate various physological and environmental factors influencing the physicochemical states of mucus secretions and to evaluate the functional significance, in terms of efficiency of muco-ciliary clearance, of such influence.